This section provides background information related to the present disclosure which is not necessarily prior art.
Many exhaust systems in the automotive field have attempted to use both active and passive valve assemblies to alter the characteristics of exhaust flow through a conduit as the exhaust pressure increases due to increasing engine speed. Active valves carry the increased expense of requiring a specific actuating element, such as an electric motor or a solenoid. Passive valves utilize the pressure of the exhaust stream in the conduit with which the valve is associated.
Either type of valve may be susceptible to problems of accelerated wear, vibratory noise, or chatter when a closing element such as a valve plate of the valve switches from an open position to a fully closed position and a portion of the valve plate contacts an inner surface of the conduit. Electric motors may be controlled to reduce the rate of valve plate movement as the plate approaches the conduit. This level of control is typically unavailable for passive valves that are loaded toward the closed position by a spring.